This week's questions

Dive, dive, dive: Cliff divers at Acapulco plunge from great height. Is there a theoretical limit to the height from which a person can survive a dive into water? If the divers reach terminal velocity, then presumably any extra height is irrelevant and therefore would a dive from an aircraft be possible.

Woolly thinking: How is "steel wool" made and when was it invented? Who had the inspiration to spot the market for this imaginative product?

An eye for colour: Why are human and cat irises brightly coloured? Is this an incidental effect of the chemicals in the iris or is there a physiological reason for eye colour?

Spreading trouble? Why are low-fat spreads unsuitable for cooking and is there any danger in using them for this purpose?

Leggy bonds: What is it that crane flies do, apart from mating with other crane flies, that requires ungainly long legs? And ...

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